Loki detected_fields query limits results in unbounded memory allocation

Medium
Advisory ID:CVE-2026-21729
Published:2026-07-15
Product:Loki
CVSS Score:7.5
CVSS Vector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Fixed Versions:
>=3.7.0

Summary

The Loki detected_fields endpoint allocates 2*limit elements in slices and maps based on the user-supplied limit query parameter, regardless of actual result count. A massive limit value (e.g. 600000000) allocates 20-30 GiB even with zero matching results, causing OOM, resulting in denial of service.